General Information

	Eli: Translator Construction Made Easy
	Global Index
	Frequently Asked Questions
	Typical Eli Usage Errors

Tutorials

	Quick Reference Card
	Guide For new Eli Users
	Release Notes of Eli
	Tutorial on Name Analysis
	Tutorial on Scope Graphs
	Tutorial on Type Analysis
	Typical Eli Usage Errors

Reference Manuals

	User Interface
	Eli products and parameters
	LIDO Reference Manual
	Typical Eli Usage Errors

Libraries

	Eli library routines
	Specification Module Library

Translation Tasks

	Lexical analysis specification
	Syntactic Analysis Manual
	Computation in Trees

Tools

	LIGA Control Language
	Debugging Information for LIDO
	Graphical ORder TOol

FunnelWeb User's Manual

	Pattern-based Text Generator
	Property Definition Language
	Operator Identification Language
	Tree Grammar Specification Language
	Command Line Processing
	COLA Options Reference Manual

Generating Unparsing Code

Monitoring a Processor's Execution

Administration

System Administration Guide

LIDO - Reference Manual

Overall Structure

A LIDO text specifies an evaluator for executing computations driven by a tree walk. A tree grammar specifies the structure of trees. Computations are associated with rules and symbols of the tree grammar. Computations may depend on one another via typed attributes.

In Eli a LIDO specification is usually composed of several components supplied by the user, derived from libraries, or generated by Eli tools. The components are combined into one file and then processed by LIGA.

Syntax

    LIDOSpec       ::=  Specification
    Specification  ::=  Specification Specification |
                     |  RuleSpec ';' | SymComp ';' 
                     |  SymSpec ';'  | TermSpec ';'
                     |  AttrSpec ';' | ChainSpec ';'

Examples

    RULE p: Stmt  ::= 'while' Expr 'do' Stmt COMPUTE
      Expr.postType = boolType
    END;

    SYMBOL Expr COMPUTE
      Compatible (THIS.preType, THIS.postType);
    END;

    ATTR preType, postType: DefTableKey;

There is no restriction on the order of specifications. Any permutation of specifications has the same meaning.

LIDO objects such as rules, symbols, or attributes are identified by their names. They are introduced by using them in LIDO constructs. There are no explicit declarations in LIDO.

Specifications associate certain properties with an object, e. g. computations are associated with a rule, or a type with an attribute name. There may be several specifications for the same object as long as the specified properties are not contradictory.

In the syntax of this document we distinguish names for objects of different kinds, e. g. RuleName, SymbName, TypeName. The syntax rules for names are omitted in the rest of this document. The following rules are assumed for XYZNames

    XYZName  ::= Identifier
    XYZNames ::= XYZName | XYZNames ',' XYZNames

All names are written as identifiers in C.

Restrictions

It is strongly recommended not to use names that begin with an underscore or which have the form rule_i where i is a number, in order to avoid interference with identifiers generated by LIGA.

RuleNames, SymbNames, and TypeNames must be mutually distinct. AttrNames must be different from ChainNames.